An ultrasound system has become an important and popular diagnostic tool since it has a wide range of applications. Specifically, due to its non-invasive and non-destructive nature, the ultrasound system has been extensively used in the medical profession. Modern high-performance ultrasound systems and techniques are commonly used to produce two-dimensional or three-dimensional ultrasound images of internal features of a target object (e.g., human organs).
The ultrasound system may transmit ultrasound signals to a living body and receive ultrasound signals (i.e., ultrasound echo signals) from the living body to form an ultrasound image corresponding to the living body. The ultrasound system may further perform a frame average process between a current ultrasound image and a previous ultrasound image (i.e., previous frame average image) by using an infinite impulse response filter to enhance quality of the ultrasound image (i.e., to improve a signal-to-noise ratio of the ultrasound image).
The ultrasound system may perform the frame average process based on a fixed frame average coefficient as the frame rate changes. However, this presents a problem since motion blurring occurs in the frame average image when the living body or a target object within the living body moves. Further, an ultrasound probe contacted on a surface of the living body is often moved.